stdlib: eliminate an inconsistent overload of == on NSString that would make == and != inconsistent in non-generic code, and that would not be used at all in generic code.
stdlib: eliminate an inconsistent overload of == on NSString that would
make == and != inconsistent in non-generic code, and that would not be
used at all in generic code.

Part of rdar://17498444

Swift SVN r20524

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation